The main difference between controlling the source of infection and cutting off the transmission route: one is to cut off the transmission of infectious diseases from the source; the other is to cut off the transmission of infectious diseases from the pathway, the fundamental purpose of both is to prevent infectious diseases from continuing to spread. Management of infectious sources, control of infectious sources, the most fundamental is mainly the early detection of infected individuals, early quarantine of contacts of infectious diseases, close observation, good drug prevention or vaccination, from the source so that the disease can not spread. Cut off the path of transmission, if the infected person is found, but do a good job of isolation and disinfection measures, clearly cut off the infectious disease process from the path, will also prevent the continued progress of the development of the disease leading to the epidemic, so the most fundamental purpose are to prevent the spread of infectious diseases and epidemics.